Recently, mobile communication systems, such as mobile telephone systems and wireless local area networks (LAN), are widely utilized. In the field of mobile communication, to further improve the communication speed and the communication capacity, communication technology in the next generation is being discussed continuously. For example, in the 3rd generation partnership project (3GPP) which is a standards body, standardization of communication standards, such as long term evolution (LTE) and LTE-Advances (LTE-A) on the basis of the LTE, is completed or under review.